1. Field of the Invention
The present invention relates to a self-leveling damper for motorcycles. More particularly, the invention relates to a self-leveling damper applicable to the rear wheel of a motorcycle.
2. Description of Relevant Art
There have been proposed a number of rear-wheel-oriented self-leveling dampers for motorcycles, such as in Japanese Patent Publication Nos. 42-11103 and 43-20487, in which a hydraulic damper provided with a cushion spring includes a hydraulically damping cylinder and a hydraulic chamber formed separately relative to the cylinder, whereby the hydraulic pressure generated in the compression stroke when a relatively large load is applied to the rear part of the motorcycle is conducted to be stored in the hydraulic chamber taking advantage of the expanding and contracting actions of the damper to raise the loading ratio of the damper relative to the cushion spring, thereby preventing the vehicle level from falling down, thus keeping the vehicle at a constant level.
However, such conventional self-leveling dampers are disadvantageous in the following points.
Namely, the sliding of a movable member as a part of the hydraulic chamber is not always smooth enough to assure a proper self-leveling effect.
Moreover, for the movable member, the returning period can not be adjusted in accordance with external variations such as of temperature and road conditions.
Further, under the state with hydraulic pressure built up in the hydraulic chamber, when the damper is caused to expand in an instant by a relatively large stroke, the hydraulic cylinder is liable to undergo a negative pressure, so that the vehicle level suddenly falls in an instant.
Furthermore, at the moment the vehicle is unloaded after stopping or parking, the vehicle level at once suddenly rises with the center of gravity of the vehicle, thus lacking stability.
The present invention has been achieved to effectively overcome come such disadvanges of conventional self-leveling dampers.